Expandable (monthly view) / collapsible (weekly) calendar widget for Android

I saw this android calendar widget used in an app called cal and was impressed.

I would like to implement a similar one in my application. I am currently using an android calendar framework called caldroid and I am using it as a snippet and is called by clicking the action bar button and will collapse by clicking on the action bar button.

But I would like to make a widget like in an application. Screenshots are attached.

I would like to know if you know you know any framework that can be used to achieve this or any approach or advice on how to code this.

I'm a little new and know the basics of Android. Haven't tried creating custom widgets yet.

Thanks, Bala